A method of optically testing a specimen exists for the purpose of measuring the turbidity of a specimen such as liquid, the amount of a specific component in the specimen, and other items. In such an optical testing method, the specimen is irradiated with light to measure light that is caused by the irradiation. More specific examples of such a testing method include a method of irradiating a specimen with light and measuring the degree of scattering of the light, a method of measuring an amount of absorption of light by a component in a specimen when the specimen is irradiated with light and the light transmits through the specimen, and a method of measuring fluorescence caused in a specimen. In such a testing method, conventionally, the specimen has been stored in a test tube or cell having an appropriate volume, such as several milliliters.
In recent years, a testing method is developed which uses a testing member provided with a fine groove for storing a specimen, as substitute for the above test tube or cell. In such a method, the test is possible even for a small amount of the specimen and thus requires only a slight amount of the specimen. Moreover, the use of a testing member having a plurality of grooves enables collective measurement and a number of specimens can therefore be tested at the same time.
Patent Literature 1 discloses a multi-layered composite structure as an example of the above-described testing member having fine grooves. The multi-layered composite structure comprises a base material that constitutes side surfaces of the grooves, a first layer that constitutes bottom surfaces of the grooves, and a resealable film as a cover that covers the grooves (paragraph 0032 and FIG. 2 of Patent Literature 1). Patent Literature 2 discloses a plastic microchip in which a plastic substrate that has a fine flow channel as the above groove at the surface and a plastic film as a cover that covers the groove are bonded together via an adhesive (claim 1 of Patent Literature 2). Patent Literature 3 discloses a microchip obtained by thermal bonding between a resin substrate that has grooves for flow channels on the surface and a resin cover member that covers the grooves for flow channels and also discloses that the resin substrate and the resin cover member are formed of polycarbonate resin (claim 1 and paragraph 0065 of Patent Literature 3).